Peri-implant hard-tissue response to hydrophilic implant surfaces in animal models: A systematic review and meta-analysis

To systematically evaluate whether hydrophilic implant surfaces are advantageous over traditional surfaces in peri-implant hard-tissue responses using controlled animal models.

This systematic review and meta-analysis was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. An electronic search of PubMed, Scopus, and the Cochrane Library, supplemented by manual searching, identified controlled animal studies comparing hydrophilic and traditional surfaces. Extracted outcomes included bone-to-implant contact (BIC), bone area (BA), and/or implant stability quotient (ISQ). Risk of bias was assessed using the Systematic Review Center for Laboratory Animal Experimentation tool.

Sixteen studies comprising 868 implants placed in 196 animals met the inclusion criteria. The overall risk of bias was moderate. A meta-analysis demonstrated no significant effect of hydrophilic surfaces on BA at 1-2 or 4 weeks. Conversely, BIC was significantly higher for the hydrophilic surfaces at 1-2 and 3-4 weeks, with a trend toward significance at 6-8 weeks, suggesting a time-dependent early effect. No significant differences in ISQ scores were observed between the groups at 2-4 weeks.

Within the limitations of the available animal evidence, hydrophilic implant surfaces are associated with enhanced early BIC but show no consistent advantages in BA formation or implant stability over traditional surfaces. These findings indicate a potential transient histological benefit of hydrophilic surfaces. However, current evidence remains insufficient to support their routine clinical application for immediate or early-loading protocols.